This invention relates to a method of processing an end portion of a shielded wire and an end portion processing apparatus.
In the case of applying an end processing to a shielded wire (or cable) including, for example, a core wire (center conductor), an inner sheath (inner layer) covering the conductor, a braid (shielding member) covering the inner sheath, and an outer sheath (outer covering) covering the braid, first, the outer sheath is stripped off or removed over a predetermined length at an end portion of the wire to expose the braid, and then the exposed braid is turned or folded back on the outer sheath, and then the exposed inner sheath is stripped off or removed to expose the conductor. Thus, these steps are carried out in this order.
A problem with this end processing is the processing of the braid. This braid, after expanded into a generally trumpet bell-shape, need to be turned or folded back on the outer sheath, and this processing is difficult.
There has been proposed a braid processing method in a related automated apparatus, in which a pair of expansion claws (punches) are driven to strike against an outer surface of the braid radially thereof, thereby expanding an end portion of the exposed braid, and then the pair of expansion claws are driven to strike against a proximal end portion of the exposed braid, thereby expanding the exposed braid into a larger size. Thereafter, a pipe is inserted to be fitted on an outer periphery of an inner sheath disposed on the inside of the expanded braid. In this condition, a braid-reversing member of a half-split shape is slid on the pipe toward the shielded wire to fold back the expanded braid on the outer sheath (see, for example, JP-A-2000-102133).
In the above related method, the expansion claws are shifted in the axial direction such that the striking of the expansion claws against the braid is carried out twice, and by doing so, the braid is expanded into a larger size before the folding-back step. However, in the second striking operation of the expansion claws, the expansion claws are driven to strike against the braid, with the end portion of the shielded wire not held by any means. Therefore, the expansion claws often struck against the braid in a bent condition of the shielded wire, and in some cases the braid was not expanded uniformly. When the braid is not expanded uniformly, the folding-back step at a later stage can not be carried out in a stable manner, and as a result the yield is lowered.